Effect of Polymer Three-Cavity Micro-Tube Extrusion Die Structure on Swell Deformation
The flow of polymer melt in the die and the swelling deformation of the extrudate directly affect the molding quality of the extruded products.In this study,based on the Carreau model,the numerical simulation method was used to study the influence of die wall thickness difference and hollowness structure characteristics on the swell deformation behavior during the extrusion process of polymer three-cavity micro-tube.The results show that the key factor affecting the extrusion swell deformation is the axial velocity distribution at the outlet of the die.The difference between the inner and outer wall thickness will lead to the increase of the thickness of the extrudate at the larger wall thickness position and the decrease of the smaller wall thickness position,and the change of the wall thickness difference has a great influence on the wall thickness deformation of the thin-walled area,up to 91.4%.When the thickness difference between the inner and outer walls is constant,reducing the hollowness can improve the uniformity of the axial velocity distribution at the die outlet and reduce the extrusion deformation by 70.1%.Finally,the shape of the die was compensated by inverse extrusion,the swell deformation law was verified,and the extrusion molding was significantly improved.The research results can guide the die structure optimization design of polymer multi-cavity micro-tube.
extrusion die structureswell deformationwall thickness differenceprofiled multi-cavity micro-tubeinverse compensation design
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